Every sewing machine has a presser foot lifter mechanism. The most common type is a simple cam lever on a pivot rod. When the lever is pushed upwardly by hand, the cam section slides under another rod secured to a spring-loaded pressure bar with a presser foot secured to the bottom of the bar. This action causes the presser foot to rise. There is a flat spot on the cam type lever. When it is in the raised position, the presser foot rests in the upper position until this lever is again pushed downwardly by hand.
A number of mechanisms are known in the prior art for lifting the presser foot on sewing machines by movement of the foot or by the knee. These mechanisms are a series of levers and pivot points permanently built into or onto the machines, and are mostly on the industrial type machines used in garment making factories.
There is some art covering this type of presser foot lifter mechanisms for use on household sewing machines. Such mechanism operate on a presser foot with a series of levers and pivot points within the sewing machines. Examples of such mechanisms are found in U.S. Pat. Nos. 4,333,407, 4,466,369, 603,988 and 1,370,069.
In the latter two patents, a series of cables, levers, brackets and pivot points are permanently built into or onto the sewing machine and are operated by foot or by knee movements. The structures of these patents eliminate the need for the simple cam type lever and pivot screw presser foot lifter mechanism. U.S. Pat. No. 603,988 covers a complete sewing machine. The presser foot bar mechanism is just one phase of the complete sewing machine.
During sewing with conventional sewing machines, there are times when a sewer wishes that he or she had a third hand. When the fabrics or materials being put together have to be placed under the presser foot in a precise manner, the material must be held with both hands. Some materials, if not held with both hands, will slip out of proper alignment and will not be sewed correctly.
During machine embroidery, for instance, the material is held in a darning hoop and held with both hands during sewing. At times, it is desirable to move the hoop to a different location. It would be more advantageous to have a device to lift the presser foot so that the work (hoop) could be held with both hands and moved. Rather than hold the hoop in place with one hand and use the other hand to lift the presser foot and reach back down to the hoop with both hands, the sewer must move the hoop to the next area of work but again let go of the hoop to reach up to the presser foot lifter and move the presser foot back down to start embroidering again.
The above problem presents a need for improvement in presser foot lifter mechanisms, especially as applied to household sewing machines.